1. Field of the Invention
The present invention relates to an assembly of collated nails for use in automatic impact nailing apparatus.
2. Description of the Prior Art
An automatic impact nailing apparatus comprises a hammering mechanism for hammering a nail into underlying material. The apparatus may be a single stroke-type apparatus in which compressed air or other means is used for setting the nail in a single stroke of the hammering mechanism or it may be a reciprocating apparatus in which the hammering mechanism comprises a movable piston or the like which moves in a reciprocating fashion to set the nail.
In both types of apparatus, nails are typically fed to the hammering mechanism from a strip or coil of collated nails. For example, in a prior known assembly of collated nails there is provided a plurality of nails which are aligned in a side-by-side fashion with the head of one nail overlapping the head of an adjacent nail. In practice, the nails in this type of assembly are held together by some sort of metallic or non-metallic bonding material. As the hammering mechanism is lowered against the head of the lead nail in the assembly, the nail is broken away from the remaining nails in the assembly and set. An assembly of nails of this type is shown in U.S. Pat. No. 4,610,381.
In another type of assembly of collated nails, the nails are held together in a stair-step or staggered arrangement by means of relatively stiff pieces of plastic. An assembly of this type is sold by Senco Fastening Systems, Cincinnati, Ohio.
A principal disadvantage of the above-described assembly is that the nails are held in an elongated relatively rigid arrangement and require a specially made elongated cartridge holder which projects outwardly from the main body of the nailing apparatus.
In another type of assembly of collated nails there is provided an elongated strip of U-shaped plastic. The parallel legs of the strip are provided with a plurality of clip-like slots for holding the nails with a mechanical clamping action. The base of the U-shaped strip comprises a plurality of sprocket holes.
A principal disadvantage of the U-shaped carrier is that it is relatively expensive to manufacture and load, is bulky and heavy. Also, the U-shaped form of the strip makes it relatively stiff and prevents its being wound into a tight compact package. An assembly of this type is sold by Duo-Fast Corporation, Franklin Park, Ill.
In another type of assembly of collated nails there is provided an elongated strip of paper or other suitable material comprising a plurality of sprocket holes. Between each pair of adjacent sprocket holes there is provided a pair of spaced slits. A nail is inserted in each pair of slits and held there as by friction and/or a bit of adhesive. Thereafter, the strip of nails is wound so as to form a compact circular assembly of collated nails. An assembly of nails of this type is shown and described in applicant's co-pending U.S. patent application Ser. No. 07/061,432, entitled Impact Nailing and Dimpling Apparatus.
In use, the circular assembly of nails is inserted in the body of the nailing apparatus. The strip is advanced by a sprocket engaging the sprocket holes. When properly positioned, the nails are torn from the strip by a movable nail feed arm assembly and positioned beneath the hammering mechanism which thereafter sets the nail.
While the circular assembly of nails described above has the advantage of being compact and insertable in a compartment within the main body of the nailing apparatus, it also has certain disadvantages. First, sprocket holes and a sprocket wheel for engaging the holes to advance the nails are required. Second, tearing the nails from the strip typically produces fibers and bits and pieces of strip material which can clog the nailer or escape from the nailer and adhere to the workpiece.